This invention relates to a closed or smooth top range in which a gas burning device provides the heat energy for cooking utensils placed on the top surface of the range and to a controlling system for the burner for providing variable heat output and safe and reliable operation.
This general type of range employs a smooth top, usually of glass ceramic material having a negligible temperature coefficient of expansion, and conventionally plural heating units, with four the most common arrangement. When the heating units are of gas type, a substantial quantity of heat is developed and accommodation must be made for dissipation of same either by way of a ducting system or more commonly by controlled venting into the kitchen area. Various expedients can be employed to achieve this function, including heat exchange between the exhaust gases and incoming air, which provides as well an increase in burner efficiency.
The thermal energy must be transmitted through an imperforate member, rather than directly to the utensil as in the common open burner configuration and heretofore the energy has been almost entirely radiant in using both electric and gas heaters. Further, consideration must be given to the spatial distribution of the source of the energy so as to attain effective transmission characteristics and avoid local hot spots and the like which can have a deleterious effect upon the top surface. Still further, inasmuch as a closed gas burning system is being employed, suitable safeguards must be provided for proper ignition on demand as well as for safe exhaust of the burned gases.